Abnormal expression and functions of proto-cadherins in human malignant tumor

Proto-cadherins (PCDHs)are a class of cadherin-like membrane proteins which can be divided into clustered PCDHs and non-clustered PCDHs.Previous research showed that proto-cadherins can regulate the development of neurons and play a role in the maturation of brain.Lately, some abnormal expressions of PCDHs have been identified in different human malignant tumors.The reduction or deficiency of PCDHs in malignant cells has certain links with cancer progression.A follow-up study suggests that PCDHs can be a tumor suppressor since these proteins inhibit the proliferation and metastasis of cancer cell.The aim of this review is to evaluate the altered expression of PCDHs and their actions during the development of cancer. Key words: Protocadherin; Malignant tumor; Tumor inhibitor